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United States Patent M 3,126,405 PROCESS FOR PREPARING ORGANIC SULFURESTER COMPOUNDS Giuseppe Losco and Giorgio Rossi, Milan, Italy,assignors to Montecatini Societa Generale per llndustria Mineraria eChimica, lVlilan, Italy No Drawing. Filed July 17, 1959, Ser. No.827,692 Claims priority, application Italy July 21, 1958 6 Claims. (Cl.260455) The present invention relates to esters of an organic aliphaticor aromatic acid with an alkylxanthoyl carbinol or with adialkyl-dithiocarbamyl carbinol.

It particularly relates to the preparation of a group of organic sulfurcompounds having the general formula in which R is a methoxyl, ethoxyl,isopropoxyl or a dimethylamino or diethylamino group, while R is amethyl or phenyl radical.

These substances can be prepared easily by reacting either a metalalkylxanthate having the general formula in which R is a preferablymethyl, ethyl or isopropyl, and Me is a metallic element, such as sodiumor potassium; or by reacting metal dialkyldithiocarbamate having thegeneral formula in which R is methyl or ethyl and Me is a metallicelement, such as sodium or potassium, each being reacted with amono-halomethyl ester of acetic or benzoic acid of the formula in whichR is methyl or phenyl and Y is a halogen atom, such as chlorine,bromine, and iodine.

The reaction is generally carried out in the presence of an inertsolvent capable of dissolving one or both reactants. As solvents,monohydric alcohols, ketones or their mixtures may be used. The mostsuitable temperatures may vary within fairly wide limits, e.g. from 10to 80 C. The duration of the reaction varies from 1 to 16 hours. It isconvenient, sometimes, to use an excess of one of the two reactants overthe stoichiometric amount.

The metal halide formed as a byproduct of the reaction can be eliminatedby filtering or by adding water. In the latter case the inorganic saltand the excess, if any, of organic salt are dissolved, there occurringalso the contemporaneous precipitation of the desired product. The mainreaction product can also be isolated by other known methods, such asconcentration, distillation, and crystallization.

The substances of the present invention are, in general, liquids whichare distillable under reduced pressure, or they are crystalline solids.They display fungicidal activity, as shown by laboratory tests carriedout on micelia of Alternaria tenuis Nees, Aspergillus niger Thiegh,Penicillium roqueforti Thom, Saccaromyces ellypsoideus Hansen and onconidia of Erisiphe cichoriacearum DC.

The following are examples of preferred embodiments of the invention:

EXAMPLE 1 27 g. of chloromethyl acetate are added to a suspension of 40g. of potassium ethylxanthate in 150 cc. of anhydrous ethyl alcohol,while cooling with ice cold water so that the temperature of thereacting mass is not higher than 25 C. When the addition is completed,agitation is continued for 3 hours at 2025 C. and the mixture is thenrefluxed on a water bath for 1 hour. The potassium chloride formed isthen removed by filtration and the liquid is concentrated under reducedpressure. The residue is treated with cc. of ethyl ether and washed withwater. The ether extract brought to dryness gives 29 g. of an oilyyellow liquid consisting of ethylxanthoylcarbinol acetate. The substancecan be obtained in the pure state by distillation under reducedpressure. Boiling point 8485 C. under 0.15 mm. Hg: S found=32.9-32.9%; Stheoretical=33.01%.

The reaction is formulated as follows:

ozi rsofisomoiiom KCl EXAMPLE 2 11.5 g. of metallic sodium and,subsequently, 30 ml. of carbon disulphide are added to 200 ml. ofanhydrous methanol. 54 g. of chloromethyl acetate are added to thesodium methylxanthate solution thus obtained; the temperature risesspontaneously to about 45 C. The mixture is heated on a water-bath for30 minutes and, after cooling, sodium chloride is eliminated byfiltration. The filtrate is concentrated under reduced pressure and theresidue is treated with ml. of ethyl ether. The ether solution, afterWashing with water, is dried on Na SO and then concentrated to dryness.

5 8 g. of methylxanthoylcarbinol acetate of the formula 0 HCHaO(I%SCH2OOCHa are obtained in the form of a slightly straw-yellowoil. The product can be obtained in the pure state by distillation underhigh vacuum. Boiling point 8183 C. under 0.1 mm. Hg: S found=36.0%35.7%,S theoretical=35.5 8%.

EXAMPLE 3 25 g. of chloromethyl acetate are added to a suspension of 40g. of sodium diethyldithiocarbamate in 150 ml. of acetone; thetemperature rises spontaneously to about 40 C. The mixture is refluxedon a water bath for 1 hour and is then cooled; the salt formed isfiltered off. The liquid thus obtained is concentrated under reducedpressure and treated with 150 m1. of ethyl ether. By operating asindicated in Example 2, 36 g. of diethyldithiocarbamylcarbinol acetateare obtained in the form of a slightly yellow viscous liquid. Thisproduct can be purified by distillation under high vacuum. Boiling point121-122 C. under 0.1 mm. Hg: S found=29. 229.1%; S calculated=28.97%. Nfound=6.46%. N calculated=6.32%.

This reaction is formulated as follows:

' II (caromwin: ciornooom II (C2H5)zNfiSCHzO 0 CH3 NaCl 3 EXAMPLE 4 34g. of chloromethyl benzoate are added to a suspension of 32 g. ofpotassium ethylxanthate in 200 ml. of acetone while stirring. Thereaction is slightly exothermic. The whole is agitated for 16 hours andis then heated to the boiling point for 30 minutes. After cooling, themixture is poured into 300 ml. of water. The oil thus formed isseparated and kept under vacuum mm. Hg) at about 40 C. until its weightis constant.

43 grams of ethylxanthoylcarbinol benzoate of the formula are obtainedas a straw-yellow liquid. S found=24.6- 24.5%. S calculated=25.0l%

EXAMPLE 5 17 g. of chloromethylbenzoate are added to a suspension of20.6 of sodium isopropylxanthate in 150 ml. of acetone while stirring.By operating as indicated in Example 4, 22 g. ofisopropylxanthoylearbinol benzoate of the formula are obtained in theform of a straw-yellow liquid. S found=22.81-23.13%. Scalculated=23.72%.

EXAMPLE 6 17 g. of chloromethylbenzoate are added to a suspension of16.9 g. of monohydrate sodium dimethyldithiocarbamate in 100 ml. ofacetone while stirring. The reaction is exothermic. The mixture is keptat 4045 C. for 2 hours and, after cooling, the whole is poured into 300ml. of water. A bulky solid product is formed which is collected on aBuchner filter and thoroughly washed with water. After drying, 24.5 g.of dimethyldithiocarbamylcarbinol benzoate are obtained.

The substance can be obtained in the pure state by crystallization frommethanol. Melting point, 86.5 to 87.5 C.

EXAMPLE 7 17 g. of chloromethyl benzoate are added to a suspension of18.8 g. of sodium diethyldithiocarbamate in 150 ml. of acetone whilestirring. After 2 hours the mixture is refluxed for 1 hour and, aftercooling, is filtered to remove sodium chloride. The liquid isconcentrated under reduced pressure and then mixed with 100 ml. of ethylether. The ether solution, after washing with 100 ml. of water andsubsequent dehydration on Na SO is evaporated.

23 g. of a straw-yellow oil are obtained. The oil is .easily solidifiedin the form of coarse crystals, Which are pressed on a porous diaphragmin order to eliminate any traces of oily substances.

By crystallization from methanol, bamylcarbinol benzoate, of the formuladiethyldithiocaris obtained in the shape of crystals having a meltingpoint of 50-51 C. S found=22.6%. S calculated=22.62%.

EXAMPLE 8 90 g. of dimethyl dithiocarbamylcarbinol benzoate (Example 6)mixed with 6.8 g. of lignin sulphite, 3 g. of expanded silica, 0.15 g.of kieselguhr and 0.05 g. of wetting agent obtained by condensation ofethylene oxide, give a preparation which can be dispersed in water andis suited for nebulization on plants.

EXAMPLE 9 50 g. of diethyldithiocarbamylcarbinol benzoate (Example 7)mixed with 40 g. of kieselguhr, 2 g. of expanded silica and 8 g. oflignin sulphite give a preparation suited for uses analogous to thosementioned in Example 8.

EXAMPLE 10 A 0.05% aqueous dispersion of the preparation of Example 8applied by nebulization under standard conditions onto young kidney-beanplants grown in pots under artificial light, inhibited blight (Uromycesappendiculatus) with which they were infected after complete drying ofthe film of product.

EXAMPLE 1 1 A 0.05% aqueous dispersion of the preparation of Example 8,applied by nebulization onto young tobacco plants grown in pots underartificial light, inhibited the oidium (Erysiphe cichoracearum) withwhich they were infected under conditions analogous to those of Example10.

EXAMPLE 12 A 0.005% aqueous dispersion of the preparation of Example 9employed by the technique of Example 12, inhibited the growth ofperonospora (P. viticola).

EXAM PLE 1 4 A 0.05% aqueous dispersion of the preparation of Example 9,employed by the technique of Example 11, inhibited growth of oidium (E.cichoracearum) on tobacco.

EXAMPLE 15 A 0.1% aqueous dispersion of the preparation of Example 9,employed by the technique of Example 10, inhibited growth of blight (U.appendiculatus) on kidney bean.

The fungicidal activity of the products according to the invention isillustrated by the following results obtained by standard laboratorymethods:

(a) Evaluation of the capacity of the products to inhibit growth anddiflusion of fungine mycelium, after absorption on filter paper,evaporation of the solvent, resolubilization and diffusion on nutritiveagar-agar.--By this technique, small filter-paper disks with 1 cm.diameter, impregnated with the solutions of the products underexamination are placed on the agar-agar coated surface of Petri dishesseeded with the test fungi. After incubation in a thermostat for 72hours the haloes of inhibition of fungine growth around those disks aredetermined, and expressed in mm. The known fungicide, sodiumpentachlorophenate, was taken as a reference for comparison. The resultsare classified as follows:

0=inhibition halo with diameter less than 1 mm. 1=inhibition halo withdiameter less than 1-2 mm. 2J=1Ilhibltl0l1 halo with diameter less than3-4 mm. 3=inhibition halo with diameter less than 5-7 mm. 4=inhibitionhalo with diameter less than 8-11 mm. 5-=inhibition halo with diameterless than 12-15 mm. 6 =inhibition halo with diameter less than 16-20 mm.7=inhibition halo with diameter less than 21-25 mm. 8 =inhibition halowith diameter greater than 25 mm.

Ethylxanthoylcarbinol 1 8 8 8 8 acetate (Ex. 1) 0. 2 8 8 8 3 0.04 3 0 0methylxanthoylcarbi- 1 8 8 8 8 1101, acetate (Ex. 2) 0. 2 8 8 8 1 0. 042 0 3 1 dunethyldithiocarbamylcarbinol benzoate 1 3 2 4 0 (Ex. 6) 0. 2 32 4 0 0. 04 2 2 4 0 diethyldithlocarbamylcarbinol acetate (Ex. 1 4 3 4 00. 2 3 l 1 0 0.04 0 0 0 0 ethylxanthoylcarbinol 1 1 1 1 0 benzoate (Ex.4) 0. 2 1 1 1 0 0. 04 1 0 0 0 iso propylxanthoylcar- 1 1 1 1 O binolbenzoate (Ex. 0. 2 1 0 0 0 5) 0.04 1 0 0 0 sodium pentachloro- 1 8 7 7 5phenate 0. 2 6 6 6 4 0.04 4 5 3 1 (b) Evaluation of the capacity of theproducts to inhibit growth and diffusion of fungine mycelium accordingto the porcelain cup method.-The cup method differs from theaforementioned method only in the use of a porcelain cup containing aconstant dose of solution of the product to be examined, in lieu ofsmall paper disks. Sodium pentachlorophenate was taken as a referencecomparison. The results obtained are classified by indexes ashereinbefore defined.

TABLE 2 Product Dose, Altem. Aspen Penicil. Sac.

Percent tenuis niger roguef. ell.

Ethylxanthoylcarbinol 1 8 8 8 8 acetate (Ex. 1) 0. 2 8 8 8 0 0.04 6 0 00 methylxanthoylcarbi- 1 8 8 8 7 ml acetate (Ex. 2) 0. 2 8 8 8 2 0.04 31 8 1 dimethyldithlo carbamylcarbinol ben- 1 2 2 1 0 zoate (Ex. 6) 0. 21 2 2 0 0.04 1 1 1 0 diethyldithio carbamylcarbinol 1 5 4 4 O acetate(Ex. 3) 0. 2 3 2 2 0 0.04 0 O 0 0 ethylxanthoylcarbinol 1 4 4 4 0benzoate (Ex. 4) O. 2 2 1 4 0 0.04 2 1 1 0 isopropylxanthoyl carbinolbeuzoate 1 2 2 1 1 (Ex. 5) 0. 2 1 0 0 0 0. 04 l 0 0 0 sodiumpentachloro- 1 8 7 8 5 phenate 0. 2 7 6 7 4 0.04 4 5 5 1 (c) Evaluationof the capacity to inhibit germination and growth of fungine mycelium,of the products incorporated in the nutritive agar-agar (streak method).The streak method allows the examination of products hardly diffusiblein solid agar-agar. By this method, the solution of the product isincorporated in the nutritive substrate, While the inoculation of thetest fungus is carried out by means of streaks with suspensions ofspores. The reading of the plates is carried out after 72 hours and thegrowth of the fungi is evaluated by indexes defined as follows:

Ono difference in respect of water as a control 1-slight difference inrespect of Water as a control 2-colonies spread through the whole streak3--some colonies at a single point of the streak 4ifungine growthlacking 6 The results of the evaluation of some products and of sodiumpentachlorophenate are reported in Table 3.

ethylxanthoylcarbinol 0. 2

benzoate (Ex. 4)

isopropylxanthoylcarbinol benzoate (Ex.

phenate sodium pentachloro- (d) Evaluation of anti-oiaial activity.Themethod used for evaluating anti-oidial activity consists in nebuliz ingunder standard conditions aqueous dispersions of the products to betested onto small tobacco plants of the Virginia bright variety bredunder standard conditions. When the nebulized product deposited thereonhas become completely dry, the test plants are infected by slightrubbing with leaves covered with oidium (Erisiphe cichoriacearum). Thedetermination of the infection is carried by estimating the percentproportion of leaf surface area covered with oidium about 15 days aftertreatment and by comparing it with the infection of untreated controls.The following 5 classes of degrees of intensity of infection were thusestablished, in growing order of concession:

1=no infection 2=considerable reduction of infection as compared withthe untreated control (10-20% against 70-90%) 3=evident reduction ofinfection as compared with the untreated control (30-40% against 70-90%)4=slight reduction of infection as compared with the untreated control(5060% against 70-90%) 5=infection as in the untreated control.

A sample of commercial colloidal sulfur was used as reference ofcomparison.

TABLE 4 Results obtained after 15 days Product Dose,

percent Dimethyldithiocarbamylcarbinolbenzoate (Ex.

diethyldithiocarbamylcarbinol benzoate (Ex. 7)

colloidal sulfur The data presented above for the compositions, found inExamples 8 and 9, and for the methods of employment and the activity ofthe compositions onplants, found in Examples 10 to 15, are not to betaken as limitative, since other carriers, dispersants and methods ofapplication will now be obvious to persons skilled in the art.

We claim:

1. Ethylxanthoylcarbinol acetate, of the formula:

2. Methylxanthoylcarbinol acetate, of the formula:

II OHIO (iSCHnOC CH:

3. Dimethyldithiocarbamylcarbinol benzoate, of the formula:

I] (CHahNCfSCHgOG 00H;

4. Diethyldithiooarbamylcarbinol benzoate, of the formula:

ll (C HQQNfiSCHiO C Cells 5. Ethylxanthoylcarbinol benzoate, of theformula:

II (3 1150 ("JSCIhO C Ca i-s 6. Isopropylxanthoylcarbinol benzoate, ofthe formula:

0 H ll CH;O-O ("3301110 C CcHs CH: S

References Cited in the file of this patent UNITED STATES PATENTS Lieberet al May 25, 1943 Hunt Mar. 19, 1946 Gresham et a1 July 5, 1949Somerville Oct. 2, 1956 FOREIGN PATENTS Italy Mar. 27, 1956

1. ETHYLXANTHOCYLCARBINOL ACETATE, OF THE FORMULA: 3.DIMETHYLDITHIOCARBAMYLCARBINOL BENZOATE, OF THE FORMULA: